This invention relates to magnetic disc drive assemblies of the class employing one or more rigid discs.
Magnetic disc drive assemblies employing rigid, or hard, discs are commonly used in desktop and other computer mainframes as a principal memory for the computer. There is a continuing need for disc drives with greater capacity. This need is met by a combination of factors, including increasing the number of tracks on a given disc. The number of tracks on a disc is established by the track density, usually measured by the number of tracks per radial inch, and the radial position of the inner and outer tracks. If the inner track is as close to the disc spindle as possible and the outer track is as close to the outer edge of the disc as possible, a maximum number of tracks for a given track density is achieved.
Present disc drives employ stop mechanisms that establish the limits of rotation of the head/actuator assembly, thereby defining stop positions of an E-block of the head/actuator assembly, thereby defining the inner and outer track positions on the disc(s). Typically, the stop mechanism employs one or more stop arms on the E-block arranged to engage one or more pins fixed to the disc drive housing. The position of the stop arm(s) to the stop pin(s) is established during manufacture of the disc drive housing, based on calculations dictated by the geometry of the actuator assembly.
In the prior art, the stop arms were mounted close to the spindle axis. Any error in the positioning of the stop surfaces (e.g., the pins and/or the engaging surfaces on the stop arm) was magnified over the longer distance between the spindle axis and the transducing heads. As a result, positioning of the inner and outer tracks was not altogether accurate.